In daily life, for exactly identifying environment and directions in the dark, illumination devices have already been indispensable tools. Most existed illumination devices have a light tube or a bulb served as a light source respectively, and further more, the light tube or light bulb may be a fluorescent light tube, an incandescent light bulb, a halogen light tube, a halogen light bulb, and so on.
Among the light tubes or bulbs, the fluorescent light tube are widely used by the most people due to the reasons of the power consumption of the fluorescent light tube is one quarter of the incandescent light bulb, the life of the fluorescent light tube is 5 to 10 times of the incandescent light bulb, the fluorescent light tube can provide homogeneous illumination, and the fluorescent light tube can be used for wide-angle illumination. Meanwhile, for providing wider-field, higher illumination values, and more modulated illumination, a plurality of fluorescent tubes and proper light modulation plates are assembled into a light box shell, so as to assemble a fluorescent light assembly being capable of providing modulated illumination. Following up, we will disclose the structure and the working principle of the mentioned fluorescent light assembly.
Please refer to FIG. 1, which is a perspective view that illustrates a conventional fluorescent light assembly being capable of providing modulated illumination. As shown in FIG. 1, a fluorescent light assembly 1 includes a light box shell 11, a plurality of crosswise light modulation plates 12, lengthwise light modulation plates 13 (only shown one in FIG. 1), paired electrode holders 14, and fluorescent light tubes 15. The light box shell has an arrangement surface 111, an illumination surface 112, and an illumination opening 113. The arrangement surface 111 is located inside the light box shell 11, the illumination surface 112 is located outside the light box shell 11 with respect to the arrangement surface 111, and the illumination opening 113 is formed on the illumination surface 112.
Each of the crosswise light modulation plates 12 is arranged between the arrangement surface 111 and the illumination surface 112, parallel to the other crosswise light modulation plates 12, and inserted into the light box shell 11. Similarly, each of the lengthwise light modulation plates 13 is arranged between the arrangement surface 111 and the illumination surface 112, parallel to the other lengthwise light modulation plates 13, vertical to the crosswise light modulation plates 113, and inserted into the light box shell 11. Meanwhile, the crosswise light modulation plates 12 and the lengthwise light modulation plates 13 are formed with wavy surfaces extended along their extension directions.
The paired electrode holders 14 are arranged on the arrangement surface 111, and the fluorescent light tubes 15 are assembled into the electrode insertion holes (not shown in FIG. 1) of the paired electrode holders 14. Each of the fluorescent light tubes 15 is parallel to the other fluorescent light tubes 15 and the lengthwise light modulation plates 13, and vertical to the crosswise light modulation plates 12.
After the fluorescent light tubes 15 project the illumination light beams, some of the illumination light beams are projected toward the crosswise light modulation plates 12 and the lengthwise light modulation plates 13, reflected from the wavy surfaces, modulated with the other illumination light beams, which have not projected toward the crosswise light modulation plates 12 and the lengthwise light modulation plates 13 yet, and then projected out of the illumination opening, so as to provide modulated illumination. Due to the related techniques are well known by most people, so that it is not described any further hereinafter.
People skilled in related arts can easily realized that, in prior arts, due to the crosswise light modulation plates 12 and the lengthwise light modulation plates 13 are directly inserted into the light box shell 11, so that they are not able to change the direction of the reflection surfaces, i.e., the wavy surfaces are mentioned, with respect to the light box shell 11. Obviously, they are not able to adjust the illumination value, which is provided to any selected region of external environment.
Nevertheless, when triggering the fluorescent light assembly lighting, the electrons released due to that the electrodes impact the particles, which are usually the particles of mercury vapor within the fluorescent light tube to stimulate the phosphor coated on the inner surface of the fluorescent light tube, which is projecting white light. However, the phosphor distributed on the inner surface of the fluorescent light tube usually contains heavy metals, such as mercury, so that it is difficult to be recycled and makes more pollution problems.
In another aspect, since a light emitting diode (LED) has the advantages of lightweight, less volume, low power consumption, and long working life, etc., and it is gradually used to illumination devices. Following up, we will provide brief description about the lighting principle of the LED. The lighting principle of LED is translating electric power to light energy, that is, doping a minute amount of carriers into a conjunction of P-type side and N-type side and continuously combining the minute amount of carriers with a major amount of carriers to form a LED. To be with the good performance of the LED radiation may need a large amount of pairs of electrons and holes.
The space charge layers become narrower when applying a forward biased voltage, and then a major amount of carriers are doped into the P-type side and the N-type side according to Fermi characteristic energy level deviation. Due to that the minute amount of carriers are increased on the P-type side and N-type side, the pairs of electrons and holes located on the P-type side and the N-type side are recombined to release sufficient photons. In the present, the categories of LED generally include AllGaP and GaN series.
Additionally, although the electric power consumption of the fluorescent light is just one quarter of the incandescent light, the working life of the fluorescent light is five to ten times of the incandescent light. But the electric power consumption of the LED is just one eighth of the incandescent light, and the working life of the fluorescent light is fifty to one hundred times of the incandescent light. Comparing with the fluorescent light, the LED not only can save electric power and work in a long life, but also can work in a lower lighting temperature. However, due to the intensity of illumination light beam of emitted from the LED is highly influenced by the value of stimulating voltage and has obviously orientation, so that it cannot provide modulated illumination toward any selected region.